1. The Field of the Invention
The present invention relates to integrated electronics. More particularly, the present invention relates to an integrated semiconductor high side switch with multi-fault protection.
2. Background and Relevant Art
Vehicles today are becoming significantly more complex and sophisticated. Much of the complexity and sophistication can be attributed to the electrical nature of vehicles. Modern automotive electronic systems, for instance, monitor or control many aspects of a vehicle's operation. Automotive electronic systems use various sensors (resistive sensors, inductive sensors, pressure sensors, and the like) to detect and monitor operational parameters such as fuel mixture, vehicle speed, engine temperature, safety mechanisms, and the like. Automotive electronic systems use the data collected by the various sensors to control and operate the respective electronic systems.
When an electronic system is designed for a vehicle, there are several problems that should be addressed. For instance, automotive electronic systems operate in a harsh environment that cannot be readily changed. Thus, electronic systems used in vehicles must survive the environment and be able to withstand extreme temperatures, nearly constant vibrations, and other physical jolts. In addition, automotive electronic systems may also be subject to extreme voltages (both high and low voltages) and short circuits to either ground or other voltage levels.
Another problem faced by automotive electrical systems is related to the need to interface a relatively large number of sensors with a microprocessor or other control system. As a general rule, it is not practical for the microprocessor to monitor all of the sensors in real time. Thus, the microprocessor samples the sensors periodically or based on current operating conditions of the vehicle. It is therefore desirable to turn the various sensors on and off rapidly. Mechanical switches are an inadequate solution for turning the sensors on and off rapidly because they are both too slow and too expensive. Electro-mechanical switches, on the other hand, have relatively short life spans, which makes them a less than ideal solution.
The need to turn a sensor on and off quickly is not the only electrical problem faced by automotive electrical systems. There are a variety of different fault conditions that can occur such as extreme voltages, short circuits to both high and low voltages, current surges, and the like. A properly designed electrical system should survive the various fault conditions and isolate other electronics that may be affected by the fault conditions. A properly designed electrical system insures that current, for example, does not flow back into a voltage supply and that voltage spikes do not harm the electrical system.
These problems are particularly present at switches that are used to turn the sensors on and off repeatedly. Not only should the sensors, supply voltages, or other electrical devices be protected from fault conditions, but the switches also need to be protected from the fault conditions themselves. One solution to these problems in use today is to provide a number of discrete electronic components that both customize the interface with the sensor or other electrical device and that protect the sensors from various fault conditions that may occur during operation of a vehicle. The use of discrete components, however, presents a potential problem in reliability because the severe operating environment of vehicles may have an adverse impact on one or more of the discrete components. The use of discrete components also raises the cost of this solution. What would be advantageous is a system or method that provides protection for various fault conditions without relying on discrete components. This type of approach would lower cost and improve reliability.